The present invention relates to a collision detection device for a motor vehicle, comprising a pressure measurement chamber, which is formed by a hose, as well as to a motor vehicle front or rear module with such a collision detection device. The collision detection device is used in particular to detect a collision of the motor vehicle with a pedestrian.
It is known to arrange an energy-absorbing element in a motor vehicle, in particular in a two-track passenger car, between a bumper cladding and a front bumper cross member, which energy-absorbing element is deformable to protect a pedestrian in the event of a collision of the motor vehicle with the pedestrian at a relatively low force level. Furthermore, a collision detection sensor based on a pressure measurement is known. The collision detection sensor serves to detect a collision with a pedestrian so that a control unit, on the basis of this detection, can actively control pedestrian protection measures, for example raising a front flap or triggering a windscreen airbag. Such a collision detection sensor includes a hose to which a pressure sensor is connected, which can detect pressure fluctuations within the hose. The hose is filled with air at atmospheric pressure. If the hose is deformed as a result of the collision with the pedestrian, a pressure change takes place inside the hose. Such a hose is usually arranged in the vehicle transverse direction in abutment against the bumper cross member and accommodated in a groove formed in the energy-absorbing element.
Depending on the configuration of the bumper cladding, the bumper cross member and/or the energy-absorbing element as well as the hose, however, there can be a need to improve the response behavior of the collision detection sensor.
According to DE 10 2012 004 766 A1, this is solved, for example, whereby an energy-absorbing element in which a hose for collision measurement is accommodated, has a particular geometry so that a compression of the energy-absorbing element is facilitated and thus a deformation of the hose in the event of a collision also takes place more rapidly. By this means, a response behavior or a signal quality of a sensor is improved.
It is furthermore known from DE 10 2013 016 239 A1 to form moldings on counter bearings of a vehicle front, which are designed in such a manner that an adjoining hose can be deformed better or more easily for collision measurement. The result is that a response behavior or a signal quality of a sensor is also improved.
It is an object of the present invention to provide a collision detection device comprising a pressure measurement chamber formed by a hose, as well as a motor vehicle front or rear module with such a collision detection device, wherein a collision-induced deformation of the hose is promoted without changing a structure surrounding the hose.
This and other objects are achieved by a collision detection device, and a motor vehicle front or rear module having such a collision detection device, in accordance with embodiments of the invention.
A collision detection device for a motor vehicle according to the present invention has a pressure measurement chamber which is formed by a hose. Furthermore, a projection is arranged on an outer circumference of the hose in such a manner that a collision-induced deformation of the hose is promoted. By this measure, a pressure variation in the pressure measurement chamber is also promoted accordingly.
As a result of the invention, a response behavior, i.e. a more rapid signal generation or a more sensitive signal generation of the collision detection device as a result of a stressing of the motor vehicle due to the collision, is improved. Furthermore, no additional measures are required to increase the response behavior at elements adjoining the hose in order to promote a deformation of the hose in the course of the collision. Furthermore, as a result of the formation of the projection on the hose, a required accuracy in the positioning of the hose is reduced so that lower requirements on manufacturing tolerances are possible. Due to the collision device according to the invention, it is possible to use these on different motor vehicles in order to increase a response behavior without needing to make a modification to the motor vehicles.
According to a preferred further development, the projection is formed integrally with the hose. In other words, the projection is formed during a manufacturing process of the hose.
Alternatively, the projection can also be connected in a firmly-bonded manner to the hose. For example, the hose can be adhesively bonded to the projection.
As a result, the hose or the collision detection device with the hose can be arranged on different vehicles and at different positions of the vehicles without it being necessary to make an adaption to the surrounding vehicle structure for this purpose to increase a response behavior of the collision detection device.
According to a preferred further development, the hose is formed from an extruded plastic material.
The hose can be manufactured cost-effectively by extrusion.
The projection can be manufactured integrally with the hose in the extrusion process in a cost-effective manner.
The hose can be formed in this case from an elastomer material and particularly advantageously from a silicone material. Such materials make it possible to achieve a particularly easily deformable hose.
In the collision detection device according to the present invention, furthermore a pressure sensor can be arranged in such a manner that it communicates with the pressure measurement chamber and the pressure sensor can be adapted to record a pressure and/or a pressure change in the pressure measurement chamber as a consequence of the deformation of the hose.
Advantageously, the projection can extend in the longitudinal direction of the hose.
Thus, a response behavior of the collision detection device with the hose can be improved over the length of the hose provided with the projection.
According to a preferred further development, the projection can extend substantially over the entire effective length of the hose and therefore the measurement chamber.
Such a hose is particularly easy to manufacture, for example, by the extrusion process and can ensure that the response behavior of the collision detection device is improved over the entire length of the hose.
The projection can, however, also only extend in sections in the longitudinal direction of the hose or the measurement chamber. In other words, a plurality of projections can thus be arranged according to a desired response behavior of the collision device.
It can, for example, be desired that the response behavior is only improved at certain positions in order to achieve an approximately same response behavior over an entire length of the collision device.
The projection can have a constant cross-sectional shape in the longitudinal direction of the hose.
Alternatively, the projection can have different cross-sectional shapes in the longitudinal direction of the hose, which bring about a desired different deformation behavior of the hose in the longitudinal direction of the hose.
As a result, the response behavior of the collision detection device or the hose with its pressure measurement chamber can be adapted according to a desired response behavior by simple means.
According to a particularly preferred embodiment of the collision detection device, a cross-sectional shape of the projection is configured to be substantially trapezoidal wherein the short side of the trapezoid is facing the hose.
As a result, a deformation of the hose can be further promoted, whereby the pressure on the hose is concentrated through the short side of the trapezoid.
Advantageously, apart from the section on which the projection is formed, the hose has a constant wall thickness.
As a result, the hose can be manufactured cost-effectively and exhibits a constant deformation behavior along its circumference.
According to a preferred further development of the collision device, the measurement chamber, i.e. an inside diameter of the hose, in the non-deformed state of the hose, has a substantially circular cross-section or an oval cross-section.
Furthermore, the present invention relates to a motor vehicle front or rear module, which has a collision detection device as described above.
In particular, a motor vehicle front or rear module with the collision detection device has a hose, which is arranged in such a manner that the projection adjoins a rigid structural element of the motor vehicle front or rear module in the collision direction and the hose is supported via the projection on the structural element.
According to a preferred further development, the structural element can be a bumper cross member, a bumper cladding and/or a cross member element above or below the bumper cross member.
Preferably, a cross-sectional shape of the hose can be configured in the vehicle transverse direction according to a desired response behavior of the collision detection device over the vehicle width.
Depending on the structure of the vehicle front or rear module over its width, a different response behavior of the hose can be required due to a different surrounding structure, which can easily be achieved by adapting the cross-sectional shape of the projection of the hose.
Furthermore, the hose can be arranged, integrated or accommodated in an energy-absorbing element, which in particular is formed from a foamed material and which is usually also designated as pedestrian protective element.
The aforesaid further developments of the invention can be arbitrarily combined with one another as far as is possible and appropriate.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.